Open System Services Porting Guide (G06.24+, H06.03+)
Table Of Contents
- What’s New in This Manual
- About This Manual
- 1 Introduction to Porting
- 2 The Development Environment
- 3 Useful Porting Tools
- 4 Interoperating Between User Environments
- Purpose of Interoperability
- The OSS User Environment
- OSS Commands for the Guardian User
- Guardian Commands for the UNIX User
- OSS Pathname and Guardian Filename Conversions
- Running the OSS Shell and Commands From TACL
- Running Guardian Commands From the OSS Shell
- Running OSS Processes With Guardian Attributes
- Using OSS Commands to Manage Guardian Objects
- 5 Interoperating Between Programming Environments
- 6 OSS Porting Considerations
- 7 Porting UNIX Applications to the OSS Environment
- 8 Migrating Guardian Applications to the OSS Environment
- General Migration Guidelines
- C Compiler Issues for Guardian Programs
- Using New and Extended Guardian Procedures
- Using OSS Functions in a Guardian Program
- Interoperating With OSS Programs
- Starting an OSS Program From the Guardian Environment
- C Compiler Considerations for OSS Programs
- Porting a Guardian Program to the OSS Environment
- How Arguments Are Passed to the C or C++ Program
- Differences in the Two Run-Time Environments
- Which Run-Time Routines Are Available
- Use of Common Run-Time Environment (CRE) Functions
- Replacing Guardian Procedure Calls With Equivalent OSS Functions
- Which IPC Mechanisms Can Be Used
- Interactions Between Guardian and OSS Functions
- 9 Porting From Specific UNIX Systems
- 10 Native Migration Overview
- 11 Porting or Migrating Sockets Applications
- 12 Porting Threaded Applications
- A Equivalent OSS and UNIX Commands for Guardian Users
- B Equivalent Guardian Commands for OSS and UNIX Users
- C Equivalent Inspect Debugging Commands for dbx Commands
- D Equivalent Native Inspect Debugging Commands for dbx Commands
- E Standard POSIX Threads Functions: Differences Between the Previous and Current Standards
- Glossary
- Index
OSS Porting Considerations
Open System Services Porting Guide—520573-006
6-16
Which Call to Use for Process Creation
Which Call to Use for Process Creation
Of the various process-create functions in the OSS and Guardian environments, you
will need to consider the features of each and match the feature to whether you need
more performance or more portability. The advantages and disadvantages of each call
follow:
•
fork() function and exec set of functions
°
More portable code without the HP extensions
°
More features than a spawning operation: see online reference pages
°
More system overhead than a spawning operation
°
Less flexible than the tdm_fork() function and the tdm_exec set with regard
to the NonStop architecture and modification of Guardian attributes
°
File opens are propagated to the child process
•
tdm_fork() function and tdm_exec set of functions
°
Less portable than the fork() function and the exec set because of HP
extensions
°
tdm_exec set of functions can be used to run a program image in another
processor, thereby providing load balancing
°
More features than the tdm_spawn set of functions: see online reference
pages
°
More flexible than the fork() function and the exec set because you can
change process attributes
°
File opens are propagated to the child process
°
Less efficient when creating many processes
°
Supports specifying maximum heap and main stack values
•
tdm_spawn set of functions
°
Flexibility to change process attributes
°
Efficient when creating many processes
°
Creates a process on another processor efficiently, thereby providing load
balancing
°
File opens are propagated to the child process
°
Supports specifying maximum heap and main stack values
•
PROCESS_SPAWN_ procedure call
°
Can create an OSS process from a Guardian program